Modeling of narrow track thin film write head fields

A thin film inductive write head suitable for 10 Gbit/in² recording density is simulated using boundary element modeling. The material was assumed to have the non-linear B-H properties of FeAlN-SiO₂ multilayers-an initial permeability of 3400 and saturation flux density of 1.9 Tesla. The simulations show that with a trackpitch of 1 μm and a gap of 0.18 μm, it is necessary to use trimmed poles and a trackwidth of 0.6 μm to achieve a written trackwidth of 0.8 μm and allow for an erased-band of 0.05 μm at each track edge. This allows 0.1 μm for track misregistration, which is within tolerance achieved by current optical servos. If focused ion beam etching is used to trim the poles from the air bearing surface (ABS), to prevent fields from the etched shoulders from disturbing data in adjacent tracks, the shoulders should be etched 0.5 to 1.0 μm from the ABS